Embodiments described herein relate generally to switch fabrics and more particularly, to the system architecture of distributed switch fabrics such as Clos networks.
Clos networks are multi-stage switch networks that provide non-blocking connections between multiple input ports and multiple output ports. A non-blocking network is a network in which a data path through the network can always be established between an idle input port and an idle output port.
A three-stage Clos network, for example, has a middle stage connected between an input stage and an output stage. Each stage includes multiple modules. Each input stage module has multiple input ports and is operatively coupled to each middle stage module. Similarly, each output stage module has multiple output ports and is connected to each middle stage module.
A distributed switch fabric having input stage modules with a large number of input and/or output ports and/or a switch fabric having a large number of modules within each stage has many connections between each stage. Thus, a large number of cables are often required to connect the stages. Further, if the switch fabric is expanded, a large number of cables must be used to connect the new stages and/or the new input and/or output ports to the existing stages. Additionally, when expanding the switch fabric to include additional inputs and/or output ports, the switch fabric typically has its operation temporally suspended.
Thus, a need exists for a distributed switch fabric having fewer cable connections. Further, a need exists for a distributed switch fabric that can expand to include additional inputs/outputs and/or additional modules within each stage without significantly increasing the cabling and/or without having to suspend operation during expansion.